From 8965c8d0b9fadce5250502af2e57125d2a418e8c Mon Sep 17 00:00:00 2001
From: Kai Liu <kailiu@fb.com>
Date: Fri, 26 Oct 2012 15:23:50 -0700
Subject: [PATCH] Add the missing util/auto_split_logger.h

Summary:

Test Plan:

Reviewers:

CC:

Task ID: 1803577

Blame Rev:
---
 util/auto_split_logger.h | 81 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 util/auto_split_logger.h

diff --git a/util/auto_split_logger.h b/util/auto_split_logger.h
new file mode 100644
index 000000000..89429b0b4
--- /dev/null
+++ b/util/auto_split_logger.h
@@ -0,0 +1,81 @@
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// Logger implementation that can be shared by all environments
+// where enough posix functionality is available.
+
+#ifndef STORAGE_LEVELDB_UTIL_SPLIT_LOGGER_LOGGER_H_
+#define STORAGE_LEVELDB_UTIL_SPLIT_LOGGER_LOGGER_H_
+
+#include "util/posix_logger.h"
+#include "db/filename.h"
+
+namespace leveldb {
+
+// AutoSplitLogger can automatically create a new log file
+// if the file size exceeds the limit.
+//
+// The template parameter "UnderlyingLogger" can be any Logger class
+// that has the method "GetLogFileSize()" and "ResetFile()"
+template<class UnderlyingLogger>
+class AutoSplitLogger : public Logger {
+ private:
+  std::string log_fname_; // Current active info log's file name.
+  std::string dbname_;
+  std::string db_log_dir_;
+  std::string db_absolute_path_;
+  Env* env_;
+  UnderlyingLogger* logger_;
+  const size_t MAX_LOG_FILE_SIZE;
+  Status status_;
+
+ public:
+  AutoSplitLogger(Env* env, const std::string& dbname,
+                  const std::string& db_log_dir, size_t log_max_size):
+    env_(env), dbname_(dbname), db_log_dir_(db_log_dir),
+    MAX_LOG_FILE_SIZE(log_max_size), status_(Status::OK()) {
+      env->GetAbsolutePath(dbname, &db_absolute_path_);
+      log_fname_ = InfoLogFileName(dbname_, db_absolute_path_, db_log_dir_);
+      InitLogger();
+    }
+  ~AutoSplitLogger() { delete logger_; }
+
+  virtual void Logv(const char* format, va_list ap) {
+    assert(GetStatus().ok());
+
+    logger_->Logv(format, ap);
+    // Check if the log file should be splitted.
+    if (logger_->GetLogFileSize() > MAX_LOG_FILE_SIZE) {
+      delete logger_;
+      std::string old_fname = OldInfoLogFileName(
+          dbname_, env_->NowMicros(), db_absolute_path_, db_log_dir_);
+      env_->RenameFile(log_fname_, old_fname);
+      InitLogger();
+    }
+  }
+
+  // check if the logger has any problem.
+  Status GetStatus() {
+    return status_;
+  }
+
+ private:
+  Status InitLogger() {
+    status_ = env_->NewLogger(log_fname_, &logger_);
+    if (!status_.ok()) {
+      logger_ = NULL;
+    }
+    if (logger_->GetLogFileSize() ==
+        Logger::DO_NOT_SUPPORT_GET_LOG_FILE_SIZE) {
+      status_ = Status::NotSupported(
+          "The underlying logger doesn't support GetLogFileSize()");
+    }
+    return status_;
+  }
+
+}; // class AutoSplitLogger
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_SPLIT_LOGGER_LOGGER_H_